Adults who have either depression or type 2 diabetes may have an increased risk of developing dementia, and the risk may be even higher for people who have both conditions, according to a new study. In the study, researchers examined the risk of dementia in more than 2.4 million people in Denmark ages 50 and older, a group that included people who had type 2 diabetes, depression or both conditions. About 2 percent of the people in the study developed dementia over the six-year study period.